In Tim McGraw's first movie roles, including Friday Night Lights and The Kingdom, the singer had some very heavy scenes to play. But his latest film, Four Christmases, is an out-and-out comedy. One of the benefits in doing the picture came from working with a bevy of A-list actors. "I got to just sit back and watch a lot of funny stuff and then get to throw in a little. A lot of my stuff was physical things that I got to do," he told Dial-Global. "So it was interesting, and the best part about it was hanging out on the set and spending long afternoons and mornings and breaks hanging out and talking with Robert Duvall, who is just a national treasure." Others in the film include Sissy Spacek, Vince Vaughn, Reese Witherspoon, Mary Steenburgen, Jon Voight, Kristin Chenoweth and Dwight Yoakam.